In some conventional disk reproducing apparatuses adapted for records, so-called laser disks, etc., data recorded on both sides of the disk is read by means of a single pickup device by having the pickup device move to both sides of the disk.
With such a disk reproducing apparatus, in the case that the disk employed is warped, the inclination of the pickup device with respect to the disk is preferably adjusted in accordance with the warp direction (tilt adjustment). In addition, the distance separating the pickup device and the disk is preferably adjusted in accordance with the disk warp (height adjustment).
For instance, in concrete terms, a known type of such a disk reproducing apparatus (Japanese Patent Application No. 66886/1989) includes a slide plate supported by a tray and movable in a radial direction of the disk, and a pivoting table pivotally supported by the slide plate and capable of pivoting upward and downward by 180.degree.. In this disk reproducing apparatus, the pickup device is mounted on the pivoting table.
However, such a configuration presents the disadvantage that it requires a large number of parts causing the apparatus itself to have a large size. Also, the inclination angle of the tray whereon the pickup device is mounted, needs to be changed in order to perform the tilt adjustment of the pickup device. Furthermore, although the above publication does not mention this fact, a separate motor as well as a decelerating device have to be installed in order to perform the height adjustment.
In order to perform the tilt adjustment in a disk reproducing apparatus capable of reading both sides of a disk by means of a single pickup device, one might consider installing linear guide shafts at each side of the disk, each guide shaft being supported so as to be capable of swinging. In such a case, fulcrums about which the guide shafts swing are set in optimum positions corresponding to the relation between the warp angle of the disk and the variation in the height position. As a result, the height is set in the operative range of the focus servo of the pickup device upon swinging of the guide shafts during the tilt adjustment. The necessity of a separate height adjustment may therefore be eliminated.
However, when as described above, the guide shafts swing independently at both sides of the disk, the structure of the apparatus, including a driving source enabling the guide shafts to swing, becomes complex. In addition, the size of the apparatus as well as the cost thereof increase.
Also, an inverting device for moving the pickup device from the guide shafts of one side of the disk to the guide shafts of the other side, has to be installed. However the structure of this inverting device is complex. This is due to the fact that the guide shafts positioned at a predetermined inclination angle through the tilt adjustment, have to be, in addition, positioned so as to allow the motion of the pickup device. Moreover, the pickup device can not move to the inverting device if the guide shafts are not adequately positioned.
One might consider disposing fixed guide shafts at each side of the disk and installing a driving source for the tilt and height adjustments housed inside a transfer unit of pickup device. However, such a mechanism is extremely complex.